SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20100252827A1
• Filed: 03/29/2010
• Published: 10/07/2010
• Est. Priority Date: 04/02/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KOEZUKA, Junichi, ASANO, Yuji
• Granted Patent: US 8,338,226 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 35/58 based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides containing free binder metal C22C29/00
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

An object is to provide a thin film transistor including an oxide semiconductor layer, in which the contact resistance between the oxide semiconductor layer and source and drain electrode layers is reduced and whose electric characteristics are stabilized. Another object is to provide a method for manufacturing the thin film transistor. The thin film transistor including an oxide semiconductor layer is formed in such a manner that buffer layers whose conductivity is higher than that of the oxide semiconductor layer are formed and the oxide semiconductor layer and the source and drain electrode layers are electrically connected to each other through the buffer layers. In addition, the buffer layers whose conductivity is higher than that of the oxide semiconductor layer are subjected to reverse sputtering treatment and heat treatment in a nitrogen atmosphere.

Claims

1. A manufacturing method of a semiconductor device, comprising the steps of:

forming a gate electrode layer over a substrate;

forming a gate insulating layer over the gate electrode layer;

forming a conductive film over the gate insulating layer;

forming a first oxide semiconductor film over the conductive film;

etching the conductive film and the first oxide semiconductor film to form a source electrode layer, a drain electrode layer, a second oxide semiconductor film, and a third oxide semiconductor film, wherein the second oxide semiconductor film is provided over the source electrode layer and the third oxide semiconductor film is provided over the drain electrode layer;

performing reverse sputtering treatment on the second oxide semiconductor film and the third oxide semiconductor film;

performing a first heat treatment in a nitrogen atmosphere after forming the second oxide semiconductor film and the third oxide semiconductor film;

forming a fourth oxide semiconductor film over the gate insulating layer, the second oxide semiconductor film, and the third oxide semiconductor film; and

etching the second to fourth oxide semiconductor films to form a first buffer layer, a second buffer layer, and an oxide semiconductor layer, wherein the first buffer layer is formed from the second oxide semiconductor film and the second buffer layer is formed from the third oxide semiconductor film.

2. The method for manufacturing a semiconductor device, according to claim 1, wherein the first heat treatment is performed at 250°

C. to 500°

C. inclusive.

3. The method for manufacturing a semiconductor device, according to claim 1, wherein the first oxide semiconductor film is formed in an atmosphere of a rare gas and a nitrogen gas.

4. The method for manufacturing a semiconductor device, according to claim 1, wherein the reverse sputtering treatment is performed after performing the first heat treatment.

5. The method for manufacturing a semiconductor device, according to claim 1, wherein the fourth oxide semiconductor film is formed in an atmosphere of a rare gas and an oxygen gas.

6. The method for manufacturing a semiconductor device, according to claim 1, further comprising the steps of performing a second heat treatment in an air atmosphere and performing a third heat treatment in a nitrogen atmosphere before forming the fourth oxide semiconductor film.

7. A manufacturing method of a semiconductor device, comprising the steps of:

forming a gate electrode layer over a substrate;

forming a gate insulating layer over the gate electrode layer;

forming a conductive film over the gate insulating layer;

forming a first oxide semiconductor film over the conductive film;

etching the conductive film and the first oxide semiconductor film to form a source electrode layer, a drain electrode layer, a second oxide semiconductor film, and a third oxide semiconductor film, wherein the second oxide semiconductor film is provided over the source electrode layer and the third oxide semiconductor film is provided over the drain electrode layer;

performing reverse sputtering treatment on the second oxide semiconductor film and the third oxide semiconductor film;

performing a first heat treatment in a nitrogen atmosphere after forming the second oxide semiconductor film and the third oxide semiconductor film;

forming a fourth oxide semiconductor film over the gate insulating layer, the second oxide semiconductor film, and the third oxide semiconductor film;

performing a second heat treatment in an air atmosphere before etching the fourth oxide semiconductor film; and

etching the second to fourth oxide semiconductor films to form a first buffer layer, a second buffer layer, and an oxide semiconductor layer, wherein the first buffer layer is formed from the second oxide semiconductor film and the second buffer layer is formed from the third oxide semiconductor film.

8. The method for manufacturing a semiconductor device, according to claim 7, wherein the first heat treatment is performed at 250°

C. to 500°

C. inclusive.

9. The method for manufacturing a semiconductor device, according to claim 7, wherein the first oxide semiconductor film is formed in an atmosphere of a rare gas and a nitrogen gas.

10. The method for manufacturing a semiconductor device, according to claim 7, wherein the reverse sputtering treatment is performed after performing the first heat treatment.

11. The method for manufacturing a semiconductor device, according to claim 7, wherein the fourth oxide semiconductor film is formed in an atmosphere of a rare gas and an oxygen gas.

12. The method for manufacturing a semiconductor device, according to claim 7, further comprising the steps of performing a third heat treatment in an air atmosphere and performing a fourth heat treatment in a nitrogen atmosphere before forming the fourth oxide semiconductor film.

13. The method for manufacturing a semiconductor device, according to claim 7, wherein the second heat treatment is performed at 250°

C. to 500°

C. inclusive.

14. A manufacturing method of a semiconductor device, comprising the steps of:

forming a gate electrode layer over a substrate;

forming a gate insulating layer over the gate electrode layer;

forming a conductive film over the gate insulating layer;

forming a first oxide semiconductor film over the conductive film;

etching the conductive film and the first oxide semiconductor film to form a source electrode layer, a drain electrode layer, a second oxide semiconductor film, and a third oxide semiconductor film, wherein the second oxide semiconductor film is provided over the source electrode layer and the third oxide semiconductor film is provided over the drain electrode layer;

performing reverse sputtering treatment on the second oxide semiconductor film and the third oxide semiconductor film;

performing a first heat treatment in a nitrogen atmosphere after forming the second oxide semiconductor film and the third oxide semiconductor film;

forming a fourth oxide semiconductor film over the gate insulating layer, the second oxide semiconductor film, and the third oxide semiconductor film;

etching the second to fourth oxide semiconductor films to form a first buffer layer, a second buffer layer, and an oxide semiconductor layer, wherein the first buffer layer is formed from the second oxide semiconductor film and the second buffer layer is formed from the third oxide semiconductor film; and

performing a second heat treatment in an air atmosphere after forming the oxide semiconductor layer.

15. The method for manufacturing a semiconductor device, according to claim 14, wherein the first heat treatment is performed at 250°

C. to 500°

C. inclusive.

16. The method for manufacturing a semiconductor device, according to claim 14, wherein the first oxide semiconductor film is formed in an atmosphere of a rare gas and a nitrogen gas.

17. The method for manufacturing a semiconductor device, according to claim 14, wherein the reverse sputtering treatment is performed after performing the first heat treatment.

18. The method for manufacturing a semiconductor device, according to claim 14, wherein the fourth oxide semiconductor film is formed in an atmosphere of a rare gas and an oxygen gas.

19. The method for manufacturing a semiconductor device, according to claim 14, further comprising the steps of performing a third heat treatment in an air atmosphere and performing a fourth heat treatment in a nitrogen atmosphere before forming the fourth oxide semiconductor film.

20. The method for manufacturing a semiconductor device, according to claim 14, wherein the second heat treatment is performed at 250°

C. to 500°

C. inclusive.

21. A semiconductor device comprising:

a gate electrode layer;

a gate insulating layer over the gate electrode layer;

a first electrode layer and a second electrode layer over the gate insulating layer;

a first buffer layer over the first electrode layer;

a second buffer layer over the second electrode layer; and

an oxide semiconductor layer over the gate insulating layer, the first buffer layer, and the second buffer layer,

wherein each of the first buffer layer and the second buffer layer has higher conductivity than the oxide semiconductor layer and is subjected to reverse sputtering treatment and heat treatment in a nitrogen atmosphere,

wherein part of the oxide semiconductor layer is in contact with the gate insulating layer and side surface portions of the first electrode layer and the second electrode layer, between the first electrode layer and the second electrode layer,

wherein the oxide semiconductor layer is electrically connectable to the first electrode layer through the first buffer layer, and

wherein the oxide semiconductor layer is electrically connectable to the second electrode layer through the second buffer layer.

22. The semiconductor device according to claim 21, wherein the first buffer layer and the second buffer layer include a non-single-crystal oxide semiconductor.

23. The semiconductor device according to claim 22, wherein the first buffer layer and the second buffer layer are a non-single-crystal film which includes an oxide semiconductor including nitrogen.